package handlers

import (
	"bytes"
	"database/sql"
	"encoding/json"
	"errors"
	"fmt"
	"io"
	"licensing-cotton/internal/config"
	"licensing-cotton/internal/database"
	"licensing-cotton/internal/models"
	"net/http"
	"time"
)

// CreateRequest 记录新的 renew 申请 (如果设备未在申请列表中)
func CreateRequest(deviceID string) error {
	var existingStatus string

	// 查询该设备是否已经有 `pending_requests` 记录
	err := database.DB.QueryRow(`SELECT status FROM pending_requests WHERE device_id = ? ORDER BY request_time DESC LIMIT 1`, deviceID).
		Scan(&existingStatus)

	if err == nil {
		if existingStatus == "pending" {
			// 如果已有 `pending` 申请，则不允许重复提交
			return errors.New("该设备已有未处理的续期申请，等待管理员审批")
		}
		// 如果 `status` 是 `approved` 或 `rejected`，则允许提交新申请
	} else if err != sql.ErrNoRows {
		// 查询时发生错误
		return fmt.Errorf("查询续期申请失败: %w", err)
	}

	// 插入新的申请（设为 `pending`）
	_, err = database.DB.Exec(
		`INSERT INTO pending_requests (device_id, request_time, status) VALUES (?, ?, ?)`,
		deviceID, time.Now(), "pending",
	)
	if err != nil {
		return fmt.Errorf("创建续期申请失败: %w", err)
	}

	return nil
}

func HandleListPendingRequests(w http.ResponseWriter, r *http.Request) {
	if r.Method != http.MethodPost {
		http.Error(w, "Only POST allowed", http.StatusMethodNotAllowed)
		return
	}

	// 管理员权限检查
	if !isAdminRequest(w, r) {
		return
	}

	// **查询所有未审批的请求**
	rows, err := database.DB.Query(`
		SELECT id, device_id, request_time, status, approved_by, approved_at, expiration 
		FROM pending_requests WHERE status='pending'
	`)
	if err != nil {
		http.Error(w, "查询待审批请求失败: "+err.Error(), http.StatusInternalServerError)
		return
	}
	defer rows.Close()

	pendingRequests := []models.PendingRequest{}
	for rows.Next() {
		var req models.PendingRequest
		var approvedBy sql.NullString
		var approvedAt sql.NullTime
		var expiration sql.NullTime

		// **扫描所有字段**
		if err := rows.Scan(&req.ID, &req.DeviceID, &req.RequestTime, &req.Status, &approvedBy, &approvedAt, &expiration); err != nil {
			http.Error(w, "解析查询结果失败: "+err.Error(), http.StatusInternalServerError)
			return
		}

		// **处理 `NULL` 值**
		if approvedBy.Valid {
			req.ApprovedBy = &approvedBy.String
		}
		if approvedAt.Valid {
			req.ApprovedAt = &approvedAt.Time
		}
		if expiration.Valid {
			req.Expiration = &expiration.Time
		}

		pendingRequests = append(pendingRequests, req)
	}

	// **返回 JSON**
	w.Header().Set("Content-Type", "application/json")
	json.NewEncoder(w).Encode(pendingRequests)
}

func HandleDeviceRequest(w http.ResponseWriter, r *http.Request) {
	if r.Method != http.MethodPost {
		http.Error(w, "Only POST allowed", http.StatusMethodNotAllowed)
		return
	}

	if !isAdminRequest(w, r) {
		return
	}

	var req struct {
		DeviceID   string `json:"device_id"`
		Expiration string `json:"expiration"`
		ApprovedBy string `json:"approved_by"`
		Action     string `json:"action"` // "approve" 或 "reject"
	}
	if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
		http.Error(w, "解析请求失败: "+err.Error(), http.StatusBadRequest)
		return
	}

	switch req.Action {
	case "approve":
		handleApprove(w, struct{ DeviceID, Expiration, ApprovedBy, Action string }(req))
	case "reject":
		handleReject(w, struct{ DeviceID, Expiration, ApprovedBy, Action string }(req))
	default:
		http.Error(w, "无效的操作", http.StatusBadRequest)
	}
}

func handleApprove(w http.ResponseWriter, req struct{ DeviceID, Expiration, ApprovedBy, Action string }) {
	expirationTime, err := time.Parse(time.RFC3339, req.Expiration)
	if err != nil {
		http.Error(w, "无效的 expiration 格式", http.StatusBadRequest)
		return
	}

	var exists bool
	err = database.DB.QueryRow(`SELECT EXISTS(SELECT 1 FROM devices WHERE device_id = ?)`, req.DeviceID).Scan(&exists)
	if err != nil {
		http.Error(w, "数据库查询失败: "+err.Error(), http.StatusInternalServerError)
		return
	}

	if !exists {
		_, err = database.DB.Exec(`INSERT INTO devices (device_id, expiration) VALUES (?, ?)`, req.DeviceID, expirationTime)
	} else {
		_, err = database.DB.Exec(`UPDATE devices SET expiration = ? WHERE device_id = ?`, expirationTime, req.DeviceID)
	}

	if err != nil {
		http.Error(w, "处理设备记录失败: "+err.Error(), http.StatusInternalServerError)
		return
	}

	_, err = database.DB.Exec(`UPDATE pending_requests SET status='approved', approved_by=?, approved_at=? WHERE device_id=?`, req.ApprovedBy, time.Now(), req.DeviceID)
	if err != nil {
		http.Error(w, "更新请求状态失败: "+err.Error(), http.StatusInternalServerError)
		return
	}

	json.NewEncoder(w).Encode(map[string]string{
		"message": fmt.Sprintf("设备 %s 已审批，授权至 %s", req.DeviceID, req.Expiration),
	})
}

func handleReject(w http.ResponseWriter, req struct{ DeviceID, Expiration, ApprovedBy, Action string }) {
	currentTime := time.Now()
	_, err := database.DB.Exec(`UPDATE pending_requests SET status='rejected', approved_by=?, approved_at=? WHERE device_id=?`, req.ApprovedBy, currentTime, req.DeviceID)
	if err != nil {
		http.Error(w, "拒绝请求失败: "+err.Error(), http.StatusInternalServerError)
		return
	}

	json.NewEncoder(w).Encode(map[string]string{
		"message": fmt.Sprintf("设备 %s 的请求已被拒绝", req.DeviceID),
	})
}

func SetAutoRenewAllDevices(w http.ResponseWriter, r *http.Request) {
	bodyBytes, err := io.ReadAll(r.Body)
	if err != nil {
		http.Error(w, "Failed to read request body: "+err.Error(), http.StatusInternalServerError)
		return
	}
	r.Body = io.NopCloser(bytes.NewBuffer(bodyBytes)) // 重置 r.Body 供后续使用

	if !isAdminRequest(w, r) {
		return
	}

	// 解析请求体中的 "enabled" 字段
	var req struct {
		Enabled string `json:"enabled"`
	}

	if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
		http.Error(w, "Failed to read request body: "+err.Error(), http.StatusInternalServerError)
		//http.Error(w, `{"error":"解析请求失败","code":400}`, http.StatusBadRequest)
		return
	}

	// 设置全局变量
	config.AutoRenewAllDevices = req.Enabled == "true"

	// 返回成功响应
	msg := fmt.Sprintf(`{"message":"AutoRenewAllDevices set to %v","code":200}`, req.Enabled)
	w.Header().Set("Content-Type", "application/json")
	w.WriteHeader(http.StatusOK)
	w.Write([]byte(msg))
}